Air-heating wall furnace



Sept-20,1949'. QM. RHODEHAMEL y2,482,369

A'IR HEATING WALL FURNACE Filed Nov. 4, 1944 v 5 sheets-sheet 1 Av-ToRA/Ey Sept. 20, 1949. c. M. RHoDEHAMz-:L 2,482,369

AIR HEATING WALL FURNACE s :Filed Nov. 4, 1944 5 Sheets-Sheet 2.

- JNVENToR'.

Lhazlas M Rhode/rame] ZM/MM A T'ro RNE y.

Sept. 20, 1949. c. M. RHODEHAMEL' AIR HEATING WALL FURNACE Fil'ed Nov. 4, 1944 5 Sheets-Sheet 5 4 lNVENToR. Charlas M /voaar/zel BY@ ATTOKNE y,

Sept. 20, 1949. c. M. RHoDl-:HAMEL AIR HEATING WALL FURNACE 5 sheets-sheet 4 Filed Nov. 4. 1944 I A INVENTOR. Chanles M R/ZQZ BY Z'.

T TORNEy.

Sept- 20, 1949. c. M. RHODEHAMEL 2,482,369

AIR HEATING WALL FURNACE Filed Nov. 4, 1944 5 Sheets-Sheet 5 IN VEN TOR.

'harlles MIZ/Z BY a Av- To/ZNEY.

Patented Sept. 20, 1949 AIR-HEATING WALL FRNAC Charles M. Rhodehamel, Alhambra, Calif., as-i signor to Commonwealth Company, Alhambra, Calif., a copartnership Application November 4, 1944, Serial No. 561,975

16 Claims.

1 This invention relates to a furnace construction, and particularly to an assemblable and disassemblable furnace construction formed of intterlocking elements, permitting the assembly of the furnace without the` use of bolts or welding andy permitting disassembly Without destruction of the several parts of the furnace.

This invention is particularly adapted for use Vwith wall furnaces of the Warm air type. Such furnaces are usually inserted into openings in a wall structure between studs and headers provided for their reception. Such furnaces are constructed with a rire box and flues around which the air passes before entry into the grill-work in the walls of a room. It is a requirement in such furnaces that the wall or any portion thereof contiguous to the furnace show but a few degrees rise in temperature. For such reason the fire box and internal lues of these furnaces are usually baliled to provide air spaces around the furnace between the heating element and wall structure to act as insulation. It is usual in such type of furnaces to construct the baffle structure as one unit for insertion in opening provided therefor in the wall.

The several parts of the furnace are either bolted or welded together, requiring a large number of operations in their construction, resultingin a costly furnace. The furnace, being bulky and heavy, is costly in shipment and handling, thus increasing the cost of installation of the furnace. Y Y

In my furnace I employ sectional elements, formed of sheet metal, which may be separately packaged or be nested in each other'to form a small package. Each of the elements is formed with interlocking joints and spacers which permit of their ready assembly on the job without the use of bolts, welding or other such means of connection. AAs a result of this method of construction the furnace'is readily assembled into a rigid structure and may be removed readily from the Wall Without any disturbance of the Wall structure.

In the case of the prior art units, should any of the elements burn out or corrode, the whole unit must be removed and the welds broken or the bolts removed at the factory and a new element introduced. In the furnace of my invention the unit may be disassembled and a new element slipped in place and the furnace reassembled without sending the furnace to the factory and without requiring la re-plastering job on the Wall,

This invention will be further described with Fig. 4 is a section taken along the line 4-4 of Fig. 3;

Fig. 5 is a section taken along the line 5 5. of Figs. 3 and 4; f

Fig. 6 is an exploded view of the furnace, showing various units and their order of assembly;

Fig. 7 is a detailed section taken along the line 1,-1 of Fig. 6;

Fig. 8 is a section taken along the of Fig. 7;

Fig. 9 is a detail showing-the method of assembly of the first element of Fig. 6;

Fig. 10 is a view partly in section, showing the construction and method of assembly of the baille construction;

Fig, 11 is a detail View of the method employed for controlling the position of the damper;

Y of Fig. 14;

Fig. r1'7 is a fragmentary View taken in the direction of the arrow as shown in Fig. 16;

Fig. 18 is a fragmentary View taken inthe 'direction shown by the arrow I8 on Fig. 14;f

Fig. 19 is an isometric detail of the burner and fire box construction; and l Fig. 20 is a fragmentary section taken along the line 28-29 of Fig. 19.

As shown in Fig. 6, the wall section, including the furnace-receiving opening, illustrated by the studding construction shown therein, is formed of vertical studs l0 and I2 vwhich 'form the ordinary studs of the Wall structure connected by headers Il and I 3. The sub-floor ofthe rooin is 'represented by M. The furnace is set into the opening formed between the floor lll, the studs lil and i2, and headers I3 and Il. f

The furnace is composed of an external baille unit formedof Vertical panels l and Vl"topvr 6, and base i5. This unit will be called the external baiile unit. An, internal baleunit is provided composed of baiiles 25 and 34 connected by a VYtop 46. This baffle unit inside the external baille unit sits upon the base I5 and is spaced from the eX- ternal baille unit. Inside the internal baille unit is a nre box and nue unit. This nre box and flue unit sits uponthe base l5 and is spaced from the internal baffle unit. The wall opening is covered by grill construction, one of Which is shown in Fig. 6. To further describe the several elements and construction andassembly, reference. may

3 be had to Fig. 6 and sectional details of other gures.

The external' .baille construction is formed of sheet metal to give a panel I,the sidesof which are bent at right angles to give flanges 2 and 3 extending in a direction exteriorly of the interior of the furnace. These flanges araciitontat their tops and bottoms'to permit the bending of the top and bottom of panel hat a 1right :angle in #a direction opposed to the direction'of bending fof the flanges 2 and 3 to give flanges 3 and 4. Panel I' is constructed in a similar manner Vto .give side flanges 2' and 3 and top and bottom flanges 4 and 5.

Panels I and Il are :connected by top 6 (see detail of Figs. 7-'9.). The top 'f6 .is formed of a panel carrying right angle bends along itswidth :tolform vflanges il and l. A baffle 6', formed with right angle flanges 8 `and 8' bent at right angles to panel 6 and with a reverse bend, is attached at such reverse .bends tothe underneath side of =pane1i6 to give a hollow bale construction shown in Figs. 4, 5, 7, and 8. These .right angle bends or filangesSandB carry holes 8a..

The exterior baille element or panel I is placed `xavithinthe opening in the wallso that the anges 2 and 3 engage the edges of the plaster, which bas-been :previously placed on the wall, at studs Ill `and I2, and :the flue .pipe A is .inserted within the flue which is provided in the wall (see Figs. i4 Iani-115:). VThe-flange 4 rests upon ,thesub-,floor I4 (see Fig 5*). The :baille unit I is placed so .that vthe :flange 3' engages the corner of the plaster at studs I2 and thelila'nge `2 ,engagesxthe :corner lof 'the v.plaster .atstud Ill. 'The flange 4 .rests upon the subelloor I4. The top :6 slides underneath the header II and over `the lilanges lI Vand I so .that .flanges 'I and I slide exteriorly of1the panels I and :I.. The depth of .'I and I is-sufcientlyfshort to .clear flanges 2 Aand 3 and 2' and 3'. The baille 6 is of a length justsulcient to:1'it .in between the `panels I vand I (see Fig. 4). The flanges 8 are notched ',(see Figs. @and 'l) to permit thepassage'of the flanges 5 and 5 Thisspaces kthe panels I .and I at the :desired idistance. The .width of ,panel 6 -is not equal :to the 1width=of panel 6 (see Fig. 5)., thus .providing clearance on the underneath side of the panel 6 for the purposesto'fbe described later.

:With fthe @lement thus positioned the floor or base plate I5 is next slid into lplace.

'.Theiiloor plate I5 is formed Aas a dished plate, zhavingupstanding ilanges I6 along the width of .the :plate and ea flange with a broad reverse lip -If'I along lthe length of the base. .the :base :I5 between the lilanges I'I :is a sub-base it81formed by ytwo reversebends forming legs `Ib zuponwhich v'the sub-base I8 sits. The sub-base lis also bent so Aas to provide transverse lips or ribs I8a to increase Ythe rigidity of the base. illhereis thus provideda clear passage for circulationlof air .underneath the sub-base I8. At one side of .the subfbase I8 is mounted a burner bracket 22 fermes by bending VSheet metal to give .llanges 23 which act as supports to provide a .clear .air passage underneath the bracket 22. Slots '(24 are provided to receive the burner, as will be described later. The width and length of the plate 272V and the width yof the -base 26 are -suchas to permit the fire box to rest on the subj'base I8 and to encloseY the bracket 22 and 'hold the fire vbox in proper position, as will be de- Vscribed'.

'The flanges 'I6 engage flanges `4 and 4 when lthe base 1I18 is slid into place as shown 4in Figs.

Mounted upon f 4 4 and 5. Thus, the base, acting with the top 6, spaces the panels I and I' and forms an interlocking box-like construction. 4vThe flanges I'I, `when the base plate is vin place, 'extend over the main oor I4 laid over the rough sub-floor I4. Flanges I7 are thus upset to give the necessary clearance to extend over the main floor and also length. The lower end of the panel is vnotched .at S28 and 29.

The bends 38 are cut away near 'the top of the panel. The Vbottom of the panel 25 is bent at a right angle in the same direction as 38 to give la bottom flange 36 extending between the notches 28. A hole B (see Fig. V"6) is provided inthe panel 25. Angles 33 (see Fig. 3) are mounted exteriorly of the panel 25 to act as lspacers and reinforcingribs as will -be described below. Mounted exteriorly of the panel isa baille element 3l. The length of the baille 3l is bent with a reverse bend Yto provide two ilanges 32 upon which baille 3'I is mounted on 25. The llanges '-32 are cut out at 3-3. The baille is also provided with a longitudinal rib 3Ia which acts to strengthen the baffle 3l and 'also provide a spacing element, as will be ldescribed below. A lhole yB is cut in baille 3| to register with the hole B' in panel V215. rlllfie baille 3I Iis thus open vat the top and bottom providing a longitudinal air circulation passage between 3l and 25. |This vertical channel is divided 4into three compartments by the vertical spacer angles 39. The vcut out yportion 33 also provides an opening for the -lateral passage of air from thesides of the upper lend 25 between the panels 3l and 25.

The panel 134 is constructed Ain a similar manner to 25, except for the addition of an interior baille. It is provided with two longitudinal ilanges 38 and a bottom flange 35 similar to 38 Yand 3B of panel 25. Ribs 33 are similarly provided. `On the exterior of the baille is mounted abailleI constructed and mounted similarly to the baffle 3| except that it has no hole B. thus composed of a panel 3l carrying flanges It is 32 and an exterior rib and spacer angle 3Ia The flanges -32 are cutaway at 33 to provide a side `opening similarly vto the side opening provided inpanel 3 I.

The baflle 34 also carries an interior baille plate 42' and 43 formed by bending sheet lmetal -to give flanges lli and channel 45. A-It is Aattached 'tothe interior of-the panel 34 by flanges 45 and channel-44.

The top 46 is formed from sheet metal by lbending the ends to form depending'flanges 48.

Underneath the top -45 is mounted the damper 58. 'Thedamper is hung on a support 48 formed by bending a sheet of metal into a V-shape. The plateends are bent in a double reverse bend to form the flanges 49' and upstanding flange 41. The baille support is spot-welded at 49' to the top 46 which ilts 'between the flanges 4l.

*The "balessupport extends lbetween the anges 48, leaving, however,:sufcient clearance'to permit .the entry ofthe panels 25 and '534, as `.will be described below.

' Straps 5|),` provided at'the apex of the hanger 49, carry a rod 52 on which the damper 58 is hung by means of hinge straps 53. Two brackets 54 mounted Von damper 58 each carry a pin 55. A hole in damper 58 is provided behind each pin 55. A damper bar 56, having a notch 51, which engages the pins 5 5 andalso` carrying notches 5|, is' provided. The notch 51 is so formed'that when the damper is pulled to one side the notch 5 1 slips easily over the pin 55 with one end en- 4tering the registering hole. When the hanger 'inovesjinwardly to the position shown at 58, the rod 56 is secured in place against the'pin 55,` preventing the rod 56 from becoming displaced.

` The vnre box and flue unit is composed of a fire box, an intermediate flue 16, and a terminal ue 8|. The units 'are' of box construction made'of Asheet metal. The fire box is formed of end walls '60 and side walls 62 and 63 covered by a top 6I. The walls 62 and 63 end in legs 64 and 66 and carry flan-ges 65 spot-welded thereto for stilening for deflecting a secondary air vstream into'the burner. One of the walls 63 carries a hole 61 and a collar 68. The'bottom of Wall 60 is cut out to receive the burner and may be covered by a removable plate. Figs; 5 and 2show the removable plate in position,whi1e Fig. 19 shows the unit :with theplate removed and the burner in position. Y y

The intermediate flue is formed of a box 16 having end cover plates 14 and 15 forming a closed boxf'A hole 12 is Vprovided in the upper 'end of the Wall 15. This carries a collar 12 adapted to make aV sliding nt with collar 68, The

opposite Awall has a hole 19 at theV other end. I

Openended pipe ilues 11 and 1S are set in the top and bottom 14 and 15. The terminal iiue 8| is a'wedge-,shaped box closed by atop 82 but open at its end 81. The flues 8| and 16 are connected by pipes 80' and 83"' connected in wall 83 and in wall 16 of the intermediate ue. An opposedv'hole 84 in the opposite wall of 03 carries a iiue pipe 85. The intermediate ue'16 is connected to re box 60 by straps lil. A baille 1 lis attached to the straps 10.

rThe next step in the assembly of the furnace comprises the introduction of the internal baille and re box units. After the external baffle has been set place asV described above, panel 25 is set in place so that channel 3| a abuts panel I and flange 30 rests on base E5. The notches 29 engage the flanges l1. This locates the panel 25. The fire box and internal ue unit are then set in' place by fitting the pipe 85 through holes B', and B and into the flue'pipe A. The legs 64 and 66 are tted over the bracket 22. This locates the iiue and nre box' unit. The panel 34 vis then set in ,place with the flange 3|a abutting panel l and notches 36 engaging the anges |1. This locates panel 34. The top 46may then be slid over the top of the panels 25 and 34. The panels enter the space between the iianges 48 and the edges of the damper hangerV 49.. The top of the flange 41 just clears the bottom of the baille 6 andthe straps 50 clear t-hetop ofthe ilanges 38 and 33. The top 5, therefore, vholds the top 46 in place and the top 46 holds thepanels separated, since the panels are held between the flanges 4B and the V-shaped hanger 49.

The burner is then introduced through the hole provided therefor by ther removal of the plate in the fire box and set onv the bracket 22 in the holes 24 provided thereforY (see Figs; 19 and 20). The pipingco'nection's are set up on the brackets: 20 and'2l providedfor such purpose (see Fig. 19).

The front and back grills are then Aset in place. They are both constructedin identical manner as illustrated in Figs. 1, 3, 5,6, 14, to 18, inclusive. As shown in detail in Figs. 14 to 18, inclusive, the ornamental frame 89 is Afformedwith a top flange 92, a bottom anglev` 9| and side lianges 90. The frame carries vertical channels 9'3 formed withV cut-out lips 94 which t in holes in flanges 92 Aand 9|. When these lips are bent over, asshown in-Figs. 14 and 18, the vertical channels 93 are held in place. f Horizontal cross channels are provided near the top'and bottom, as shown at 95`an'd |01 in Fig. 14. Vt:Ehesechar'n'ie'ls also carry lips 95 (see Fig. 18)l which enter holes provided in 93. The channels are held in place bybending the lips 95. The channels 95 and V|01 arelocked in Vplace and cross-brace the channels 93.

A plurality of grill channels |02 (see Figs. 1,16, and 14) are set in channel 95v through holes |0| provided' inV channel 95. The vportionsv of the channels' |02 passing through the v,holes |0| into the angle -95 are distorted so as toweclge the channels in the holes. A panel 91 having back- Wardly extending flanges '98 and 99 is mounted on the channels |02 bypassing the-channels |02 through appropriate holes |00 provided in the ange 98. When these channels are introduced into the holes |00, the depending portions of the channels |02 passing through the holes |00fare distorted to wedge the channels in place. Aremovable grill door- |05 is provided underneath the panel 91. It is composed of an upper channel |06`and lower channel |01 and a plurality of channels A|05 which pass through appropriate holes provided in upper channel |06 and in lower channell |01. When they channels |05' are inserted into these holes the entering portions of the channels |05 are distorted to wedge them in place. 'I'he upper channel '|06 carries knobs The upper channel |06 has a detent |08 which engagesv the detent-receiving hole |03 in 99. The `bottom channel |01 has a detent |69 which engages a detent-receiving hole |04. The channel 89 has an'upwardly bent portion H0; The door may be set in placeby setting the channel |01 against H0' which'causes the engagement of the detent |09 with.- the detent hole |04, and the door is then pushed into position llliatil the detent element |08 Aengages the hole Mounted upon the 'back of the grill assembly isl a baille ||3A having rearwardly extending ilanges I 8 at the top and bottom anda liange 5 extending forwardlyon both sides of the panel |`|3 (see Figs.r14 to' 1'1). The panel ||3 carries an internal panel l I9 spot-welded thereto. Mounted on the insideof panel 91 (see Figf 16) and spot-Welded thereto are four straps H2'. They pass through holes I6 and H1 providedV in baille 3 (see Figs. l5 to 17, inclusive). YThe t'rapsholdthe bailles |13 andY ||9 onto the baffle To mount this grill assembly, the flange 92 is inserted underneath the top @and the flanges 95) are inserted-'inside the panels and 2 (see Figs. 3 and' 5). "The rearwardly extending flange of channel 89 is placed on top ofthe flange |1'of 7 spectively, vby four screwspprovided therefor. The rear grill is of the same construction and is inserted in -thesame way.

While the grillconstruction has been described as composed .of Vvertical channels |02 .and |05, they may be substituted Aby louversoriother types of grillconstruction.

As described above the assembly of the furnace is facilitated by spacers and interlocking flange constructions. The uni-t is made strong and substantially rigid by the same interlocking arrangement. Thus, the Weight of the 'nre vbox and flue construction resting upon the base I5 holdsthe outside panels I and 2 in position -due to the interlocking of the-.channels I6 and 4 and 4'. The interlocking of the channels 5 and 5 at the top of the panels I and 2 and the positioning of ythe `channels 5 and 45' in the recess of the flanges 8 position and hold securely .the top l'of the panels I and 2. The abutment of the `channels 41 :and -41 against the :underneath ,side of the baffle 6 transmits the weight of .the internal fire box construction to the'top'46, thus holding dow-n the vertical panels 35 and `3i. 4The vpos-itioning and the locking of the .unit .are insured by the .grill-*work by means of the fflanges 9U which engage and 'bear against the panels I and I v.and Yby the channel 92 which .engages the top 6. The panels 25 and 34 are additionally spaced -and braced by the interlocking of rthe anges .38 .and .3,8' with the channels `9|.. This interlocking braces the unit. However, the interlock is a 4sliding type ,in that ta small .relative movement of the interlocking elements lof the unit is permissible. Thus, when the unit is heated an accommodation of relative expansion of one unit with'respect tothe other is made possible.

The baiile construction forms a highly eincient .heat insulation, preventing the transmission .of `heat to .the wall structure. Thus, the heating is almost substantially entirely by convection and not .by radiation. When the fire 'is the heated air `passes through the front or rear grill through i102 thereof, .depending upon -th'e positioning of the damper 58. -A portion of the cold air passes between the ,bales Iv-.I3 and I I9 and between the ballles I|9 Iand 9-.'I in order .to keep the .front panel 91 cool. Portions of the cold air also pass upwardly between the baille I and .baffle 3|, between the baflle 3| andthe panel 25. In like manner cold air -entering the rear grill passes between the baiile lI and baille 31| between the baille 3l and the panel 25', and between the panel 25 and the baiiles 45 `and M'. In addition, the top of the furnace is also baiiled by means of the dead-air spaces between the damper hanger 49 and the -top 4S, between -t-he top 4E and the bottom of .plate 6', and between 6 and 6. Air circulation is provided by means of the holes 8a in flanges 8. The re `box is insulated from the :door .I4 by means of the air passageways provided between the angfes I-.b and underneath Athe bracket 22. In this; manner 8 the temperature .of the `surrounding woodwork andthe floor is not raised above room temperature by more than 90F.

While I have described a .particular embodiment of my invention for the purpose .of illustration, it should be understood that Various modications and adaptations thereof may be made within the spirit of the invention as set forth in the appended claims.

l. A furnace structure adapted to be inserted into an .opening in theV Wall of a structure provided in said Vwall `structure to receive said furnace, comprising an external balile unit formed to be placed in ysaid opening, said external baille unit being `composed Iof vertical panels, said vertical panels being vdisposed in opposed spaced parallel relation, and a top, composed of a panel horizontally disposed across the space between the upper edges of the vertical panels, flanges on'said verticalpanels, the flanges of said vertical panels extending horizontally and transversely .of the faces of said vertical panels, means adjacent the ends of the top engaging the flanges of the vertical panels in interlocking slidable relationship in a direction longitudinally of said flanges, said ilanges and means holding said vertical panels `in spaced relation with each other and in engagement with said top, a base for said furnace, said base being disposed initransversely siidable engagement'therewith between the lower ends of the vertical panels to hold them in spaced apart relationship, .a fire box and ue unit demountably mounted upon -said base and positioned in spaced relation with said panels and top, and a grill construction disposed over the opening dened by the vertical panels, top, and base, whereby it is adapted to cover the opening into which the Afurnace is to be placed in the wall.

2. A furnace structure adapted to be .inserted into an opening in the wall of a structure provided in said wall structure to receive said furnace, comprising an external baffle unit formed to be placed in Vsaid opening, said external baffle F unit being composed of vertical panels, said vertical panels being disposed in opposed spaced parallel relation, and a top, composed of a panel horizontally disposed across the space between the upper edges of the vertical panels, angcs on said vertical panels, the flanges of said vertical panels extending Yhorizontally and transversely of the faces oi such vertical panels, means adjacent the ends of the top engaging the flanges of the vertical panels in interlocking slidable relationship in a direction longitudinally of said anges, .said anges and means holding said vertical panels in spaced relation with each other and in engagement with said top, a base for said furnace, said base being disposed in transversely slidable engagement therewith between the lower ends of the vertical panels to hold them in spaced apart relationship, a nre box and ilue unit demountably mounted upon said base and positioned in spaced relation with said panels and top, and a grill construction disposed over the opening dened by the vertical panels, top, and base, whereby it is adapted to cover the opening into which the furnace is to be placed in the wall, `saidV grill construction comprising flanges extendingrearwardly from the outer face of said grill construction and engaging the inner faces of said vertical panels and said top and said'base to space and hold said top, base, and vertical panels in spaced relation.

3. A furnace structure formed to be inserted 9 into an opening in a wall structure Yand upon the floor upon which said wall Vstructure is placed, which comprises vertical panels, Asaid vertical panels being disposed in opposed spaced parallel relation, vertical flanges along the vertical edges thereof, said flanges beinghsubstantially perpendicular to said vertical panels and extendingin a direction away from the interiorof said furnace structure to engage the edges of the opening in the wall, top and bottom flangeson Vsaid panels, said last-named anges on said vertical panels Aextending horizontally and transversely of the faces of such vertical panelsna -top composed of a panel horizontally disposed across thespace between the upper edges of the vertical panels, depending flanges for said top, said depending flanges being slidable in a direction longitudinal of said top flanges of said vertical panels and in engaging relation to said top flanges of said vertical panels, a baille, said baille being formed with yreverse flanges extending in a horizontal direction transversely of said depending anges'for said top and attached to the underneath side of said top to space said baille fromthe underneath side of said top to'provide an air space, notchespositioned in said reverse flanges vat the ends thereof and underneath said top of length and width greater than the width and thickness of the top flanges of said vertical panels, the widthof said baille between said reverse flanges being substantially less than the Width of said top whereby said top may be slid intoposition over said top flanges of said panels, said top flanges passing through saidV notches to hold said panels in spaced relation with each other and in engagement with said top, a base for said furnace, said base-,being disposed in transversely slidable engagement therewith between the lowerv ends of the vertical panels to hold them in spaced apart relationship, a fire box and flue unit demountably mounted upon said base and positionedv in spaced relation'with said panels .and top, and a grill construction disposed over the opening defined bythe vertical panels, top, and base, whereby it is adapted Ato cover the opening into which the furnace is tobe placed in the wall. v L '.7

4. A furnace structure formed to be inserted into an opening ina wall structure and upon the floor upon which said wall structure .is placed, which comprises verticalv panels, said vertical panels being disposed in opposed spaced parallel relation, flanges alongthe verticaledges thereof, said flanges beingsubstantially perpendicular to said vertical panels and extending in a direction away from the interior of said furnace structure to engage the edges of the opening in the wall, top and bottom flanges on said panels, the flanges of said vertical panels extending horizontally and transversely of the faces of such vertical panels, a top composed of a panel horizontally disposed across the space between 'the upper edges'of the vertical panels, depending flanges for said top, said depending flanges being slidable in a direction longitudinal of said top flanges of said verticalpanels and in engaging relation to said top flanges of said vertical panels, a baille, said baille being formed with reverse flanges extending in a horizontal direction transversely of said depending flanges for said top and attached to the underneath side of saidtop to space said baille from the underneath side of said top to provide an airspace, notches positioned in said reverse flanges at the ends thereof and underneath said top of length and width greater than the width and thickness ofthe top flanges of said vertical panels vand the width of said baflle bea tween said reverse flanges being substantially less than the width of said top whereby said top may be slid into position over said top flanges of said panels, said top flanges passing through said notches to hold said panels in spaced relation with each other and in engagementlwith said top, a base for said furnace, said base being disposed in transversely slidable engagement therewith between the lower ends of the vertical panels to hold them in spacd apart relationship, a fire box and flue unit demountably mounted upon said base and positioned in spaced relation with said panels and top, a grill construction disposed over the opening defined by the vertical panels, top and base, whereby itis adapted to cover the opening into-which the furnace is to be placed in the wall, said grill construction comprising ilanges extending rearwardly from the outer face of said grill'along the length of said grill and formed to engage the inner faces of rsaid vertical panels when said grill is placed in position, and a ange along the width of said grill extending rearwardly from .theouter face of said grill and positioned to be inserted underneath said topin the space providedbetween the end of said top and the flange of saidbaillawhen said grill is placed in position, said grill engagingsaid bottom when said grill is in position. Y

5. A furnace structure formed to be inserted into the wall of a'structure and into an opening on each side of said wall .between studs and Vheaders provided in said wall structure to receive said furnace, comprising an external baille unit adapted to be vplaced against said studs and headers, said external baille unit being composed of Vertical panels said vertical vpanels beingrdisposed in opposed spaced parallel relation to engage theinwardly facing surfaces of a pair of adjacent wall'stud's, a top composed of a panel horizontally disposed across the space between the vuprzer edges of the vertical panels, top flanges on the vertical panels, the flanges of said vertical panels extending horizontally and transversely of theVv faces of suchyertical panels, means adjacent the ends of the top engaging the flanges of the vertical panels ininterlocking sliding relationship in a direction longitudinally of said flanges and at a right angle to the plane of the wall wherein the furnace is adapted to be located, said flanges and means holding said vertical panels in spaced relation with each other and in Y engagement with said top, a base for said furnace,

said base being disposed intransversely slidable engagement -therewith between the lower ends of the Yvertical panels to hold them in spaced apart relationship, an internal baille unit comprising vertical panels slidably positioned on said base within the space between ythe vertical' panels of said external baille unit, said vertical panels of said internal baille unit being disposed in opposed spaced parallel relation, "a top for said internal baffle Vunit extendingV horizontally over the space between, and slidably positioned on, the top of said last-named vertical panels and slidably positioned underneath the top positioned on the vertical panels of said external. baille unit, a spacer mounted on the exterior of and extending between each of said vertical panels of the internal baille unit andthe vertical panels of Vthe external baille unit, said spacers spacing said panels from said first-mentioned panels when said panels of said internal baille structure are placed in position in said furnace upon said base, a re box and-flue nnit'demountably mounted uponsaid base and' positioned in spaced relation with and between said vertical panels oi-the internal baffle unit and underneath the top of said internalbaie unit, a grill construction disposedoVer each of the openings' denedby the vertical panels, top and-base, whereby said grill construction is adapted` tocover thel openings each side of the wall into which the furnace is to be placed in the wall, meansv to selectively direct-heat from said re box outwardlythrough said grills, saidnieans including a damper mountedonthe underneath side of thetop, which is positioned on the vertical panels of said internal b'aille-unit I above vsaid fire box and flue unit, and means for moving said damper on said mounting between said grills toselectively direct the heat from said fire box and-flue'V unit through said grills,

6g furnace structure' forniedto be inserted into the wallof a structure and into an opening en each' sideoi said wall between studs and headers providedin saidwallV structure to receive said furnace, comprising an external baille unit f ornied to-be placed against saidstuds andv head-l eljs, said eritelnal bailie unit being composed of vi'ertizalv panels, said vertical panels being disposedin opposed spaeedjparallel relation toengagevv the inwardly facingsurfaces of a pair of esilaeeet ,Well Studs enrfe top eempesed. 0f 'e Dell-e1 lho'zomelly dSRQSlV 'aQrOSS the Space be twe nLtlie upper edges of theI vertical-panels7 flanges on said yerti ca1`panels', the flanges of` said Vettieelpenels exteeflieaheliizentelly and transversely ofthe faces oi sucia verticalpanels, means eeieeeet the ends 0f the tepeeseeng. theteneee r 0f vthegverteal. penderie..interlocking sliding ,relatioriship. ,in a ldir e-Ltion longitudinally A of, said iiariges andai; a right angle tothe plane of the wall wherein the furnaee is adapted Vtoebe placed,

Seid..flenseseridsmeene heldng seid zvertieel y Pegel@ in, .,Seid. spaced` reletieleL with.4 eaenether .j engagement. with. Seidgte'ix a besepen said bettein; flanges. `er1. Seid Yvertieal panels thezboitemengeseffSeidLi/ettieal panels extend.- inehetizeetally .eneltrensrerselref Ythe feeee of Steh vertical regels-, Seid Ytias/.e beingrdiepesed in trensrersely Slielatle .c engagement between, c the lewer; eeelsgfeiseid ,vertical panels en theaijd bettemf flanges, Saldi `tese .Seatingerid. holding Seipeenelsin 'spaced apart relationshpwith ea'eh einen; eepieternel baffle' unitreemerisine Vertical panels 'slidably` positioned *ion said base' within the, $133.0? i-btwel, .the Vertical panels 0f Sadfex rternai baffle unit, said vertical panels of said internalnbaiile unit being disposed jinopposed 'Seeeed perlellelprelatienael ten for Said. ,internal baie'unit horizontally and slidably positioned on the top oi said vertical panels of said interior baiiie unit and `slidaloly positioned underneath-the top positioned on the vertical panels ofsaid externai baiile unit, a spacer mounted on the exterior ofeachofthevertical ypanels of the internal baile unit and extending between said last-named parie ls and the vertical panels of the Aexterior baiile ,unit, `said spacers spacing said last-named panels from said rst-mentioned panels Vwhen said panels of said, int ernal ba1ile unit are placed in position insaid'iurnace upon said base, a iire bex, and .fiile unitdemeuntebly invented upon. Seid base and positioned in spaced relation withfand betweensaid vertical panels of ltheintr'e'rnalb aiiie unit and underneathsaidjlast-named top of said initieel. baille uniti@ gtl'l'eensltreton elitendine Drenthe Openings .0a each' Side.A of V the Well inte whichv said furnace is placed,'said grill construction lacing eachf disposed over the-openings deiined by the'- vertical panels; top-,andV base,V whereby each is adapted 'tocoverthe opening in each side ofthe wallinto whicli'the furnace is to'be placed in the wall; each-y gril'lfcomprising flanges extending rearwardlyv froml the'outerv'face of said'grill and forrredtoengage the inner faces oisaid nrst-named--vrtical upanels -ande said first-named top and thesaid base', saidgrills spacing'and holde in g saidiirst-n a' ,med"top,` base, and rst-nafmed veticalpanelsin'spaced relation, means tofselectivelydireetlieatffrom said i'ire box outwardly tlirough said grills, Ysaid means includingv a dampermounted"on the underneath side 'ofVV saidW topewlfiich is'mou-ntedon the vertical panelsl of saidinternalbaffle unit above said fire box and flue unit, andjxrieaiistfor moving said damper on saidvmqunting between said 'grills to selectively direct'the-hat-from said re boxand flue unit through said gri-11s,

7: A fiirnacer strueture formed to be insertedinte thewal1fof a-structure between studsA and headersprovided-in-said wall structureto reeiv'e-said furnace,` comprising' an lexternal baille' u-iit-frmed}to be plaoedeagainst 'said studs and headers; said eXternlfbaiile unit beingcomposed oi vertical panels; said-vertical 4panels being disp"osedfin-v opposedspaced-*parallel :relation tov engage the linwardlyfacing surfaces of avpair of adjacent wall'studs; andlaI top composed of a panel. -hori'zontallvdisposedacross the spacev betweenthe upper e edges -f ofthe vertical Y panels; flanges on said-1f vertical 'L panels;` the-flangesofsaid vertical panels extending `lnori2.ontally 4and trai-i'sverselyofv the-faces of-*said Vertical panels, meansad'jace'nt -the endsoithe top engaging the anges -o`fthe evrti'cal vpant-31's in interlocking `relationship -in-adir`ectiori longitudinally of said flanges amel-#atAA aJ right angle to th'e plane of the'-wa1lwhereinthe. furnace-is4 adapted to be placed; aid-anges and-mansl'iolding said vertical p` nelsiiiesaidf spaoedrelationship with each other-Sand iin engagement Y with said! topi a base for saidfurnaeafbottom anges onsaid vertical panels, the bottonr flanges of saidfvertical panels extending horizontally and transverselyY oi the faces-of fsucli vertical vfpariels,r said base being dispos ed in' transversely' slidable engagement vonV the lower ndslof said vertical -panels and 'on said bottom anges andfspa'c'ing and'holding said panels inspaced-ap'art relationship to eachI other, an internal baiilerunit comprising vertical panels slidabl-y positioned-on'sa-idfbase within the space between the vertical'panels of said external baille unit, saidverti'call lpanelsV of saidl internal baffle unit being disposed inl opposed spaced.v parallel relation; a topiorA saidf-internal'baiileunit horizont'ally and slid'ably positioned` on the top of said vertical-'panels-of said internal baille unit and sl-ida'bly Lpositioned -underneath the -top :positioned on the vertical?panelsA of said-external baffle unit, baffles mounted ori-andspaced from the exterior surface of said Verticall'p'anels of the internal baffle/unit, a-spa'c'er mounted on the exterior of each iofsa-idrlalst-named bafesand 4 extending between said-baiiies and" theY Vertical panels of the `external-lo'aiile unit, said spacers spacing said lastnamed"'panelsfromI said vertical panels" of the -internal baffle unitwhen said panels of'said internal baille unit are' placed in position in said furnace upon "said-base, a fire boxand flue unit demountably 4mounted upon said base and` positioned in spaced relation with andibetween the vertical panels of the internal-baleunit and! underneath 'the top oisaid iterna1-balile1u`nit;-anda grill lcon--` struction disposed rover the opening defined by the vertical panels, top,-and base, whereby it is adapted to cover the opening into which the furnace is to be placed in theiwall.

, A8. Afurnace structure formed to be inserted into the wall-.of a structure and into openings on both sides of Vthe wall between studs and headers provided in said wall structure to receive said furnace, comprising an external baffle unit formed to be placed against said studs and headers, said external baille unit being oomposedof vertical panels, said vertical panels ,being` in opposed spaced parallel relation to engage the inwardly facing surfaces of a pair of adjacent wall studs, and a top composed of a panel horizontally dis- .posed across the space between the upper edges of the vertical panels, flanges on the vertical panels, the .flanges of said vertical panels extending horizontally and transversely of the faces of such vertical panels, means adjacent the ends of the top engaging the flanges of the vertical panels in interlocking sliding relationship in a direction longitudinal of said flanges on said vertical panels, said flanges and means holding said vertical panels in said spaced relationship with each other and in engagement with said top, a base on said furnace, bottom flanges on said panels, the bottom flanges of said vertical panels extending horizontally and transversely of the faces of such vertical panels, said base being dislposed in transversely slidable engagement between the lower ends of said vertical panels and on said bottom flanges and spacing and holding said panels in spaced apart relationship to each other, an-internal loafile unit comprising Vertical panels slidably positioned on said base within the space'between the vertical panels of said external baille unit, said vertical panels of said internal baille'unit being disposed in opposed spaced parallel relation, bailles mounted on' and spaced from the exterior surface of said last-named panels, a panel top for said internal baffle unit'horizontally and slidably positioned over the top of said vertical panels of said internal-baille unit and slidably positioned underneath the top `positioned ont-he vertical panels of the external baille unit, a spacer mounted on the exterior of each of said last-named bailles and extending between said bailles and the vertical panels of the external baffle unit, said spacers spacing said vertical panels of the external baille unit from said vertical panels of the internal baille unit when said panels of said internal baille unit are placed in said furnace upon base, `a ilre box and flue unit demountably mounted upon said base and positioned in spaced relation with and between the said vertical panels ofthe Vinternal -baiile unit and underneath the top of said internal baille unit, a grill construction disposed over each of the openings defined by the vertical panels, top, and base, whereby said grill construction is adapted to cover the openings Aon each side Iof the wall into which the `furnace is to be placed in the wall, each of said grill constructions comprising flanges extending rearwardlyfrom thel outer face of said grill and formed to engage the inner faces of said firstmentioned vertical panels and said rst-mentioned top and said base, each of said grills spacing and holding said first-mentioned top, base, and first-mentioned vertical panels in spaced relation, means to selectively direct heat from said `fire box outwardly through said grills, said means including a damper mounted between the underneath side of said top on Athe vertical panels of said internal baille'unit and said re box and flue unit, and means for moving said `damper on said mounting between saidgrills to selectively direct the heat-from said re box and flue unit through said grills. v 4 Y 9. A furnace `structurefformed to be inserted into the wall of va structure and into openings on Vboth sides of the wall between studs and headers provided in said wall structure to receive said furnace, comprising an external baffle unit formed .to be placed against said studs and headers, said external baille unit being composed of rvertical panels, said vertical panels being disposed in opposed spaced parallel relation to engage the inwardly facing surfaces of a pair of adjacent wall f studs, and a top composed of apanel horizontally disposed across the space between the upper edges of the `vertical panels, flanges lon said vertical panels, the flanges of said vertical panels extending horizontally and transversely of the faces of said vertical panels, means adjacent the ends of said top engaging the flanges of said Vertical panels in interlocking slidable relationship in a direction longitudinally of said flanges on said verticalipanels, said flanges and means holding said vertical panels in said spaced relationship with each other and in engagement with said top, av base on said furnace, bottom flanges on the vertical panels, the bottom flanges of said vertical panels extending horizontally and transversely ofthe faces of such vertical panels, said base being disposed in transversely slidable engagement between the lower ends vof said vertical panels and on said bottom flanges and spacing and holding said vertical panels in spaced apart relationship to each other, an'internal baille unit comprising vertical panels slidably positioned on said base within the space between the vertical panels of said external baille unit, a panel top for said internal baille unit horizontally and slidably positioned over the top of said vertical panels of the internal baille unit and slidably positioned underneath the top positioned on the vertical panels of said external baille unit, a spacer mounted on the exterior of each of the Ivertical 'panels of the internal baille unit and extending between the said last-named panels and the panels of the externalbaiile unit, said spacers spacing said vertical panels of the internal baille unit Afrom the vertical panels of the external baille unit-when said panelsof said internal baille unit are placed in position in said furnace upon said base, a fire box and flue unit demountably mounted upon said 4base and positioned in spaced relation with and between the vertical panels of the internal baille unit and underneath the top of said internal baille unit, a grill construction disposed over each of the openings defined by the Vertical panels, top, and base, whereby each grill is adapted to cover the openings on each side of the wall into which the furnace is to be placed in the wall, each said grill construction comprising flanges yextending rearwardly from the outer lface of said grill and formed to engage the inner derneath side o f said top mounted on the vertical panels of said internal baille unit and said lire box and l'flue "unit,` fand v`meansfor lrrloving said `damper on said rnounting `-betweensaid-"grills to selectively direct the I'-heatiirorn said Lnre lboxan'e'l .due unit through said grills.

lli). A iurnace'struc'ture forined lto'b'e inserted into the wall of -a structure and Yinto openings .onboth sidesof the wall between studs'and head'- Aers 'provided in'fs'aidwall `strur'sture-to free'eivefsaid =furiaee,- comprising-'anexternalbaffleunit'fformed toffbe xplaced against vsaid `studs l and headers, said panels; said --vertical panels .being :disposedzin-opposed spaced parallel relation -to engage :the vinwardly `facingsurfaces of 'apair 'offadja'cent wall studs i 'and a--top composed` of a. panel :horizontally disposed across `the space between the :upper edges of the vertical -panelsg'iangeso'nthe .vertical panels, the flanges of said vertical Ipanels eX- ftending herzontaily andftmnsverselyofrthe faces .of said vertical panels, means 'adjaoentthe ends :of said top eng-aging theliianges of said :vertical fpan'els, said topengaging-tlieiianges of said .vertia cal panels in. interlocking .and slida-ble irelation`- ship in a ldirection longitudinally fsaid flanges for said vertical panels, said'an'ges vandimeans holding said vertical panels in Said spaced relationship with eachotherfandinengagernent with said top, afbase on saidJdurnaC'e, ,bottoinaanges on saidverticalpanels,'the1bottonianges of said Vertical panelsextendinghorizontallyandftrans- -versely of the faces Voi suchY fvertialwpanels, fs'ai'd Abase being :disposed -in vtransversely slidable er1- gageinent `between the 'lower ends ,of said panels and on said bottorn'anges and spacing and holding said vertical panels `in spaced apart relation .fshi'p to each other, an internal "bale :unit oomprising vertioalpanels slidably positioned fon Isaid base within the spacebetweenithe vertical'panels of said external `Vbafe tunit, a Vpanel ftopifor said internal bale vunit slidably and horizontally ;po sitio'ned over the top r,of said vertical panels fof said internal 'baffle `unit and slidably :positioned -underneath the topl positioned on the vertical :panels of the external Ybailie Vunit, fa'spacer :mounted'on the exterior of :each-or" said vertical panels .o the internal baille `unit yand extending between the said vertical panels-'of the internal bafllennit and the vertical panels l,of ,the'external .baille unit, -said` spacers spacingsaid :last-namedspanels lfroni :said iirst-rnentioned `panels when :said Vertical :panels Iof said Vinternal .-bailie lunit areplaoedin .position iin said 'furnace rupon -said fbase, a vfire .box and nue unit gderoeuntablymounted-upon :said 'base and vpositioned in .spaced ,relation with and between said yvertical -panels of Vlthe iinternal .bafe unit and .underneath said .last-.named top, .a-'grill :construction `disposed ...over V eachof the openings defined-by Ithe wertical panels, top, A`and base,- whereby said-,grill construction ris @adapted zto cover the openings on .each fsideof rthe Wall .into which the ,furnace lis -to-be placed in l the wall, each said #grill construction coomprising `vertical `entenl lingrearwarellpy' .ironithe outer .face :of the grill and .formed tongage the inner faces foi-.said.iiist-iiaznecl-vertical panelsand Said firstnaniedtop and saidlbaseancl spacing andholding :said `nrst-naznedftop, Ybase, and .first-named verti `cal panels spaced relation, leachsaidgrill .construction f'having. Apesforate .top and `bottom portions and an imperforate `center portion, bafes -mounted the interior fof 7said Agrill upon `said :central portion, toselectively-.direct heat .from said fire box outwardly Ithrough cachot said grills, said means .including :a damper .mounted between thev verticalypanels `or -saidinterilal baille 16 Luna andthe underneath smeer-said tcp @est tier-'led leilitne said -verticalfpanels 'of saiddnternal ba'ie -uriit above sadv-'re ybox and ue unit,and means f or moving-'said dan'ip'r -n -said mounting 'between saidgrinste-selectively direct-heat from `lsa ireboxand il'ue unitthrougllsaidgrills lA lfurnace structure formed tobe A'inserted iinto the Wallof astructure and into openings-eri bothsideslof vthe ivalll'lbetween 4studs and headers :provided .in said `t'vallstructure yto receive said iurziaee, :comprising 'anexternal -baile .unit Aformed 2te besplaced .against hsaid :studs .and headers, said external baiile unit-being composed :of vertical panels; said :vertical panels being disposed 'inope posed:spacedlparallel .relation .to engage the Sine wardly acing surfaces .of .anpair vof adjacent V.wall studs, and-a top composedof a-pahelihorizontally disposed across the space between the upperiedges `of :the .vertical panels, flanges on .the yvertical lpanels, the=flanges1oi said vertical panels extend; ing horizontally andtransversely `of the ffac'es of V:such VV.vertical panels, `.rneans adjacent sthe ends .of =said top .engaging the flanges of 4said vertical fpanels, saidftop engaging the flangesfoisaid:verti leal apanels inninterloclring slidable relationship ,inga direction longitudinally lof said anges ,-for -s'aid vertical panelasad langesfand means holdfingsaid vertical .panels in said spaced relation- :ship with each other .and in @engagement with saidttop, a Vbase `on said furnace, v`bottom flanges on said vertical rpan'els, the 'bottom flanges of lsaid vertical panels extending horizontally and transversely of the -faces of such ivertical -paralela Y.said base being disposed in transversely slidable lengagernentbetweenthe lower ends-of said panels and en -said bottomanges and spacing andiholdiing said panels in spaced apart relationship -to reach other, an internal baille unit comprising .vertical panels fslidably .positioned'onfsaid .base within thespace between the @vertical :panels oi said external fbaiflelunit, a .panel top :iorrsaid ,internal baie frunit horizontally and slidably pesi- .tioned on :the top'oisaid vertical panelsfoi said internalrbaiile untandslidably positioned under- ;neath -the top positioned -on the vertical panels oisaidfexternallbaflegunit, baiesfrnounted errand fspaced from the exterior surface lof said .vertical panels-of said internal balile unit,;aspacermountie.d0.n.the .exterior .of each of said last-named fbairles andfextending between said lbailes and the vertical panels .of the fexternal baffle unit, 1said rspaeersspacingssaid last-.named panels fronisaid -first-mentioned panels when said Vertical 4panels' oisaid Linternalballe Aunit'are placed in position ,in saidfurnaceupon said -base,.a.re box land ue funitdemountabl-y V`mounted upon said .base and 4Apositioned in spaced `relation `with and between saidvertical Vpanels of said linternal `baffle unit ,and .underneath the top 4of said internal 4baffle funit, a ,grill construction ldisposed over each lof Itheopenings defined .by the vertical panels, vvtop, andbase, wherebyY said grllconstruction is adapt- .ed toooverrtheiopenings Aon each -sideof the Wall ,in-to which :the furnace is .to :be placed in the fwall, each `said grill construction having a :perioratetop andlbottom portion andan imperforate Acenterportion baffles lrnountedfon the-interior of .said grill upon said eentralportion means fto selectively direct heat from saidre box out'- .Wardly through said grills, said lrneans including :ra .damper mounted between the underneath side :of -said `top on thewertical panels of said internal .balesunit andlsaid re rboxfand :nue unit, and -fmeans for Vmoving said damper on said lmounting `zbetween said ,grillsftoiseleotively vdirect lthe heat 17 from said fire box and flue unit through said grills.

12. A furnace structure formed to be inserted into the wall of a structure and into openings on both sides of the wall between studs and headers provided in said wall structure to receive said furnace, comprising an external baille unit formed to be placed against said studs and headers, said external baille unit being composed of vertical panels, said vertical panels being disposed in opposed spaced parallel relation to engage the inwardly facing surfaces of a pair of adjacent wall studs, and a top composed of a panel horizontally disposed across the space between the upper edges of the vertical panels, flanges on the Vertical panels, the flanges of said vertical panels extending horizontally and transversely of the faces of such Vertical panels, means adjacent the ends of said top engaging the flanges of said vertical panels, said top engaging the flanges of said vertical panels in interlocking slidable relationship in a direction longitudinally of said flanges for said V-ertical panels, said flanges and means holding said vertical panels in said spaced relationship with each other and in engagement with said top, a base for said furnace, bottom flanges on said vertical panels, the bottom flanges of said vertical panels extending horizontally and transversely of the faces of such vertical panels, said base Ibeing disposed in transversely slidable engagement between the lower ends of said panels and on said bottom flanges and spacing and ,holding said vertical panels in spaced apart relationship to each other on said base, an internal baille unit comprising vertical panels slidably positioned on said base within the space between the vertical panels of said external baille unit, a top for said internal baille unit horizontally and slidably positioned on the top of said panels of said internal baille unit and slidably positioned underneath the top on the panels of the external baille unit, baliles mounted on and spaced from the exterior surface of said vertical panels of said internal baille unit, a spacer mounted on the exterior of each of said last-named bali-les and extending between said bales and the vertical panels of the external baille unit, said spacers spacing said last-named panels from said rstmentioned panels when said vertical panels of said internal baille unit are placed in position in said furnace upon said base, a fire box and flue unit demountably mounted upon said base and positioned in spaced relation with and between said vertical panels of said internal baille unit and underneath the top of said internal baille unit, a grill construction disposed over each of the openings defined by the vertical panels, top, and base, whereby said grill construction is adapted to cover the opening on each side of the wall into which the furnace is to be placed in the wall, said grill construction comprising flanges extending along the length of said grill and rear- Y 18 heat from said lire box outwardly through said grills, said means including a damper mounted between the underneath side of said top posi` tioned on the vertical panels of said internal baille unit and said fire box and flue unit, and means for moving said damper on said mounting between said grills to selectively direct the heat from said fire box and flue unit through said grills.

13. A furnace structure adapted to be inserted into an opening in the wall of a structure provided in said wall structure to receive said furnace, comprising an external baffle unit formed to be placed in said opening, said external baille unit being composed of vertical panels, said vertical panels being disposed in opposed spaced parallel relation, and a top composed of a panel horizontally disposed across the space between the upper edges of the vertical panels in slidable relationship with the tops of the vertical panels, means adjacent the ends of the top engaging the top of each of the vertical panels in interlocking relationship, means holding said vertical panels in spaced relation with each other and in engagement with said top, a base for said furnace, said base being slidably disposed between the lower ends of the vertical panels, a fire box and flue unit demountably mounted upon said base and positioned in spaced relation with said panels and top, and a grill construction disposed over the opening defined by the vertical panels, top, and base, whereby it is adapted to cover the opening into which the furnace is to be placed in the wall.

14. The furnace structure defined in claim 13 in which said grill construction comprises flanges engaging the inner faces of said vertical panels.

15. The furnace structure defined in claim 14 characterized by an internal baille unit comprising Vertical panels positioned within the space between ea-ch of the vertical panels of said external baille unit and said fire box, said vertical panels of said internal baille unit being disposed in opposed spaced parallel relation, a top for said internal baille unit extending across the space between said vertical baflies of said internal baffle unit, said grill including also channels positioned to engage said vertical panels of said internal baille along the length thereof.

16. The furnace structure defined in claim 13 characterized by an internal baffle unit comprising vertical panels positioned within the space between each of the vertical panels of said external baille unit and said fire box, said vertical panels of said internal baille unit being disposed in opposed spaced parallel relation, a top for said internal baille unit extending across the space betweten said vertical baffles of said internal baille um CHARLES M. RHODEHAMEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

